Preprints
There are 5493 Preprints listed.
Uncertainty quantification of geological model parameters in 3D gravity inversion by Hessian informed Markov chain Monte Carlo
Published: 2021-12-17
Subjects: Earth Sciences
Geological modeling has been widely adopted to investigate underground geometries. However, modeling processes inevitably have uncertainties due to scarcity of data, measurement errors, and simplification of modeling methods. Recent developments in geomodeling methods have introduced a Bayesian framework to constrain the model uncertainties by considering additional geophysical data into the [...]
Tectonic controls on geomorphology and spatial distribution of monogenetic volcanoes in the Central Southern Volcanic Zone of the Andes (Argentina)
Published: 2021-12-16
Subjects: Geology, Geomorphology, Tectonics and Structure, Volcanology
Monogenetic volcanoes are among the most common volcanic landforms on Earth. The morphology and distribution of small volcanoes can provide important information about eruption dynamics and tectonics. The Southern Volcanic Zone of the Andes (CSVZ) comprises one of the most active magmatic regions on Earth. Characterized by the presence of polygenetic volcanoes and calderas in a complex tectonic [...]
Causes of the Arctic's Lower-Tropospheric Warming Structure
Published: 2021-12-16
Subjects: Physical Sciences and Mathematics
Arctic amplification has been attributed predominantly to a positive lapse rate feedback in winter, when boundary-layer temperature inversions focus warming near the surface. Predicting high-latitude climate change effectively thus requires identifying the local and remote physical processes that set the Arctic’s vertical warming structure. In this study, we analyze output from the CESM Large [...]
Mineralogy and diagenesis of Mars-analog paleosols from eastern Oregon, USA
Published: 2021-12-16
Subjects: Physical Sciences and Mathematics
Ancient (4.1-3.7-billion-year-old) layered sedimentary rocks on Mars are rich in clay minerals which formed from aqueous alteration of the Martian surface. Many of these sedimentary rocks appear to be composed of vertical sequences of Fe/Mg clay minerals overlain by Al clay minerals that resemble paleosols (ancient, buried soils) from Earth. The types and properties of minerals in paleosols can [...]
Detection of organic carbon in Mars-analog paleosols with thermal and evolved gas analysis
Published: 2021-12-16
Subjects: Physical Sciences and Mathematics
Ancient, buried soils, or paleosols, may have been preserved in the geological record on Mars, and are considered high-priority targets for biosignature investigation. Studies of paleosols on Earth that are similar in composition to putative martian paleosols can provide a reference frame for constraining their organic preservation potential on Mars. However, terrestrial paleosols typically [...]
Matched Field Processing accounting for complex Earth structure: method and review
Published: 2021-12-16
Subjects: Geophysics and Seismology
Matched Field Processing (MFP) is a technique to locate the source of a recorded wavefield. It is the generalization of plane-wave beamforming, allowing for curved wavefronts. In the standard approach to MFP, simple analytical Green's functions are used as synthetic wavefields that the recorded wavefields are matched against. We introduce an advancement of MFP by utilizing Green's functions [...]
Hermann Löns’ “Quintär” – an early approach to the geological stratigraphy of the Age of Humans and its significance in geosciences
Published: 2021-12-16
Subjects: Earth Sciences, Geology, Other Earth Sciences, Stratigraphy
In 1908, Hermann Löns outlined the concept of a Quintär” (“Quintary period”) to describe geological and biological manifestations of the Age of Humans. His definition of the “Quintary” consisted of two components: a lithostratigraphic (“Quintary deposits” or “Quintary stratum”), and a faunistic (“Quintary fauna”) one. With a view on the stratigraphic component, Löns already anticipated the [...]
Copper availability governs nitrous oxide accumulation in wetland soils and stream sediments
Published: 2021-12-15
Subjects: Biogeochemistry, Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Engineering, Geochemistry, Life Sciences
Denitrification is microbially-mediated through enzymes containing metal cofactors. Laboratory studies of pure cultures have highlighted that the availability of Cu, required for the multicopper enzyme nitrous oxide reductase, can limit N2O reduction. However, in natural aquatic systems, such as wetlands and hyporheic zones in stream beds, the role of Cu in controlling denitrification remains [...]
Challenges and uncertainty in plot-scale emissivity and surface temperature estimation using flux tower measurements
Published: 2021-12-15
Subjects: Physical Sciences and Mathematics
Land surface temperature (LST) is a preeminent state variable that controls the energy and water exchange between the Earth’s surface and the atmosphere. At the landscape-scale, LST is derived from thermal infrared radiance measured using space-borne radiometers. At the plot-scale, the flux tower recorded longwave radiation components are inverted to retrieve LST. Since the down-welling longwave [...]
Global trends in novel stable isotopes in basalts: theory and observations
Published: 2021-12-14
Subjects: Physical Sciences and Mathematics
The geochemistry of global mantle melts suggests that both mid-ocean ridge basalts (MORB) and ocean island basalts (OIB) sample lithological and temperature heterogeneities originating in both the upper and lower mantle. Recently, non-traditional stable isotopes have been suggested as a new tool to complement existing tracers of mantle heterogeneity (e.g., major and trace elements, radiogenic [...]
Filtering ground noise from LiDAR returns produces inferior models of forest aboveground biomass in heterogenous landscapes
Published: 2021-12-14
Subjects: Environmental Monitoring, Environmental Sciences, Forest Sciences, Research Methods in Life Sciences
Airborne LiDAR has become an essential data source for large-scale, high-resolution modeling of forest aboveground biomass and carbon stocks, enabling predictions with much higher resolution and accuracy than can be achieved using optical imagery alone. Ground noise filtering – that is, excluding returns from LiDAR point clouds based on simple height thresholds – is a common practice meant to [...]
A continuous vertically resolved ozone dataset from the fusion of chemistry climate models with observations using a Bayesian neural network
Published: 2021-12-14
Subjects: Atmospheric Sciences
Continuous historic datasets of vertically resolved stratospheric ozone, support the case for ozone recovery, are necessary for the running of offline models and increase understanding of the impacts of ozone on the wider atmospheric system. Vertically resolved ozone datasets are typically constructed from multiple satellite, sonde and ground-based measurements that do not provide continuous [...]
Adaptive Mesh Refinement Strategies for a Novel Modelof Immiscible Fluid Flow in Fractures
Published: 2021-12-13
Subjects: Civil and Environmental Engineering, Computational Engineering, Engineering
In this paper, we consider two Adaptive Mesh Refinement (AMR) methods to simulate flow through fractures using a novel multiphase model. The approach represents the fluid using a two-dimensional parallel-plate model that employs techniques adapted from lattice-Boltzmann simulations to track the fluid interface. Here, we discuss different mesh refinement strategies for the model and compare [...]
Thermochemical structure and evolution of cratonic lithosphere in central and southern Africa
Published: 2021-12-10
Subjects: Earth Sciences, Geochemistry, Geophysics and Seismology, Mineral Physics, Physical Sciences and Mathematics, Tectonics and Structure
The thermochemical structure of the subcontinental mantle holds information on its origin and evolution that can inform energy and mineral exploration strategies, natural hazard mitigation and evolutionary models of the Earth. However, imaging the fine-scale thermochemical structure of continental lithosphere remains a major challenge. Here we combine multiple land and satellite datasets via [...]
Elevated Post K-Pg Export Productivity in the Gulf of Mexico and Caribbean
Published: 2021-12-10
Subjects: Earth Sciences, Geochemistry, Paleobiology, Paleontology, Physical Sciences and Mathematics
The global heterogeneity in export productivity after the Cretaceous-Paleogene (K-Pg) mass extinction is well documented, with some sites showing no change on geologic timescales, some demonstrating sustained decline, and a few showing a somewhat surprising increase. However, observational data come from sites so widespread that a key outstanding question is the geographic scale of changes in [...]